In a large saucepan add the water and sugar over a medium-high heat. Bring to the boil, stirring to dissolve the sugar.
Once boiling point has been reached, continue to gently boil for a further 3 minutes before taking off the heat. Allow the sugar syrup to cool.
In the meantime, juice the lemons and limes into a large bowl. I do this on a set of kitchen scales so I can measure when I have reached the right about of juice. Which is 4 cups ( 35 fl oz or 1 liter) of lemon and lime juice.
Once the sugar syrup has cooled, add the lemon and lime juice and combine them.
Pour the cordial in to clean jars to store in the fridge for 1 week or freeze for 3-6 months.Mix 1-2fl oz (30-60 ml) of lemon lime cordial with 1 cup of water to dilute and enjoy your homemade lemon and lime cordial! Cordial can be served over ice and mixed with a soda water for a lime lemonade.